Charge distribution and hyperfine interactions in the vicinity of impurity sites in In2O3 doped with Fe, Co, and Ni

Author(s)

Sena, C. ^[1] ; Costa, M. S. ^[1] ; Munoz, E. L. ^[1] ; Cabrera-Pasca, G. A. ^[1] ; Pereira, L. F. D. ^[1] ; Mestnik-Filho, J. ^[1] ; Carbonari, A. W. ^[1] ; Coaquira, J. A. H. ^[2]

Affiliation

^[1] Univ Sao Paulo, Inst Pesquisas Energet & Nucl, BR-05508000 Sao Paulo, SP - Brazil

^[2] Univ Brasilia, Inst Phys, Nucleo Fis Aplicada, BR-70910900 Brasilia, DF - Brazil

• Document type: Journal article
• Source: Journal of Magnetism and Magnetic Materials; v. 387, p. 165-178, AUG 1 2015.
• Web of Science Citations: 16

Abstract

In this paper, first-principles calculations based on density functional theory (DEL) were used to determine TM (TM = Fe, Ni, Co) and Cd impurity locations in the In2O3 host structure, their charge states, the electronic and structural relaxations induced in the host lattice as well as to interpret previous and supplementary experimental results of hyperfine interactions. Different techniques were carried out to characterize TM-doped In2O3 bulk samples prepared by the sol-gel method starting from very pure metals. Perturbed angular correlation (PAC) spectroscopy, a sensitive nuclear technique capable of measuring interactions from electronic charge and spins within an atomic distance, was used to experimentally determine hyperfine interactions at cation sites of In2O3 doped with Co and Ni using In-111 -> Cd-111 as probe nuclei. Room temperature results of magnetization measurements in In2O3 doped with Fe, Co and Ni show ferromagnetic ordering coexisting with a paramagnetic behavior for all samples. Results of PAC spectroscopy and DEC calculations show that TM atoms locate as second nearest neighbors of Cd probes preferentially occupy symmetric sites of the doped In2O3 crystal structure with lattice parameters slightly different from that of pure In2O3. Moreover, while a major population of Cd-111 probes observes almost the same hyperfine interactions measured for pure In2O3, a small population detects magnetic dipole interactions with magnetic hyperfine field at Cd probes of 2.6 T. 3.1 T. and 4.6 T, respectively for Ni, Co, and Fe doping presenting an almost linear dependence on the number of unpaired 3d electrons of the transition metal impurity. (C) 2015 Elsevier By. All rights reserved, (AU)

• FAPESP's process: 12/11104-9 - Atomic scale investigation of high-dielectric-constant nano-structured semiconductor oxides by means of a nuclear technique
• Grantee: Artur Wilson Carbonari
• Support Opportunities: Regular Research Grants